Method of rolling profiled sections from sheet metal



Mm 12,1940. E. PENKALA $3,737

METHOD OF ROLLING PROFILED SECTIONS FROM SHEET METAL Filed June 19, 1937Patented Mar. 12, 1940 UNITED STATES METHOD OF ROLLING PROFILE!)SECTIONS FROM SHEET METAL Emil Penkala, London, England, aasignor ofonehalf to Metal Trim Limited, London, England, a

British company Application June 19, 1937, Serial No. 149,220 In GreatBritain January 26, 1 937 1 Claim.

This invention relates to an improved method and apparatus for theproduction of profiled sections by rolling from sheet metal.

. Usually the bend or corner is the weakest 5 part of a profiled sectionformed from sheet metal by rolling owing to the fact that the lateralstretching of the metal at the bend, which stretching is communicated tosome extent to the adjacent walls or flanks of the section, re-

suits in substantial thinning of the metal at the bend and consequentlythe section is of unequal thickness and is naturally weakest at thebend.

Furthermore, in bending up an L or U or 16 similar section longitudinalstretching of the edges of the metal stripis liable to occur in themethods heretofore employed and it is obvious that any pressure appliedat or near the edges of the strip will tend to increase this lon- 20gitudinal stretching action.

The present invention has for its object to enable profiled sections tobe produced wherein the bend or corner of the section is at least asstrong as the remainder of the section, and,

if desired, may be made of greater strength than the remainder of thesection, without applying pressure on parts of the section which havebeen stretched or are subject to stretching in a lateral or longitudinaldirection during the profiling operation. I

The invention also has for its object to enable profiled sections to beproduced with bends or corners which are sharp or angular externally orwith bends, corners and/or edges rein- 88 forced by flanges, beads orother forms.

According to the present invention, the improved method of forming aprofiled section by rolling from sheet metal includes the step ofupsetting the metal in a lateral direction or dia rections to form apart or parts of increased thickness and of any desired shape whereby.

the profile produced by subsequent bending of the material may bemodified and reinforced. Thus, prior to a bending operation of, forexample, 68 an L or U section, the parts at which the metal is to bebent may be thickened up or reinforced in such manner that when bent upthe corner of the section is of sharp angular form externaly. or otherdesired shape. Furthermore, the marginal edges of the section may bebeaded, flanged or otherwise provided with enlargements. Morespecifically, the invention includes a method of producing profiledsections by rolling from sheet metal wherein, prior to the forl mation,or to a stage in the formation, of a bend other projection or thickeningfor the purpose diagrammatic drawing, in whichor corner in the section,the metal thereof is upset so as to flow towards the position of thebend or corner while passing between rollers shaped to prod... e a ribor angular or other projection or thickening at the position of the bendor corner. The extent of the upsetting action and the shape and size ofthe projection or thick ening thereby produced may be such that when thesection is bent to its final shape the bend is of true angular formationexternally with- 10 out any reduction in thickness of the section at anypoint or points, with the result that the bend actually will be thestrongest part of the section. Obviously other forms ofreinforcement maybe provided, for instance, the bend may be 15 formed with an externalreinforcing rib or even with an externally projecting flange.

In the case of comparatively soft metals, the step of upsetting themetal may be effected in the cold, but in the case of steel, theinvention includes the step of local heating of the strip material atand/or adjacent the parts to be upset, such heating preferably beingeffected immediately prior to the upsetting operation, it beingunderstood that the material passes continuously from the upsettingrollers to the profiling rollers.

In some cases two or more upsetting operations, if necessary inconjunction with two or more heating operations, may take place at 80various stages in the production of a profiled section.

The formation of the part or parts of increased thickness may beeffected by the use of rollers adapted to exert an upsetting pressure onthe appropriate parts of the metal while confining the edges of the sameso that the metal is constrained to flow towards a position or positions*at which at least one of the rollers is grooved or relieved to allow ofthe formation of a rib or w described.

The invention is hereinafter described by way of example with referenceto the accompanying Figure 1 is a diagram illustrating the inherenttendency to thinning of the metal where a bend is formed;

Figure 2 is a similar view illustrating the manner in which a sharpangled section is produced 50 according to the invention;

Figures 3 to 6 are cross-sectional views illustrating the methodaccording to the invention as applied to the production of a sharpangled L section; u

Figure '7 is a cross-sectional view illustrating the manner in which asharp angled U section may be formed; and

Figures 8 and 9 are cross-sectional views S110W- ing examples ofmodified sections capable of being produced according to the invention.

When the metal strip I is bent up to form an angle section la, as shownin Figure 1, there is a tendency for a thinning of the metal to occur atthe bend so that the thickness indicated at 0 will be less than theinitial thickness 1) of the strip. This thinningtendency is due to thefact that the cross-sectional area indicated by the cross-hatching at dhas to be made up by flow of the metal in the walls of the sectiontowards the bend during the-profiling operation. Thus, in order to avoidany substantial thinning of the metal at the bend it is usuallynecessary to effect the profiling operation under. considerable pressuresufllcient to cause a fiow of the metal towards the bend.

In accordance with the present invention and as shown in Figure 2, themetal strip l is first formed with a suitably shaped projection portionlb so that when the strip is bent up to form the angle la the thicknessof the metal at the bend actually is greater than the thickness of thewall of the section and obviously the projection lb may be shaped tosecure a sharp external angle, as shown. Inasmuch as the preliminaryformation of the projection lb may be of such crosssectional area as toobviate any necessity for effecting a flow of the metal of the sectionwalls towards the position of the bend, it is clear that the profilingoperation may be effected under considerably less rolling pressure thanheretofore.

Referring more especially to Figures 3 to 6, the improved methodaccording to the invention consists in first subjecting the metal stripl to an upsetting operation, preferably with the prior application oflocalised heating so as to form the projecting rib lb, and thereafterpassing the strip between profiling rollers by which it is bent up tothe desired profiled form, the profiling-operation preferably beingcarried out in accordance with my copending application Serial No.149,217, filed June 19, 1937, so as to avoid any stretching of the edgesof the strip and also to localise the application of the rollingpressure to the parts of the section which are not stretched or subjectto stretching either in a lateral or longitudinal direction during theprofiling operation.

In one embodiment and in the application of the invention to theproduction of a sharp angled L section, the strip l is first passedbetween electrodes 2 or other heating means whereby the portion of thestrip at which the bend is to be formed is locally heated to facilitatethe upsetting operation which, as shown in Figure 4, may be effected bypassing the strip l between rollers 3 and 4 arranged to exert anupsetting pressure, the roller 4 having flanges 4a serving to confinethe edges of the strip whereby the metal is caused to flow in thedirection of the arrows and thereby upset the locally heated metal atthe centre to form the projecting rib lb. Thereafter the strip i ispassed between profiling rollers 5, 6 and l, 8 which preferably areprofiled according to the teaching of said copending application so thatthe rolling pressure is localised at the parts a at 'eteral orlongitudinal stretchthis purpose the upper rollers so that the outerparts thereof diverge out cily in relation to the corresponding profiledfaces of the respective lower rollers G and 8 so as to form an angle of3 degrees therewith, while the lower rollers 6 and 8 are formed withcentrally disposed circumferential recesses 6a, 8a respectively. Ifnecessary the profiled section may be finished by passing betweencalibrating rollers the profiles of which corre- 1sfond exactly to theprofiles of the finished sec- By upsetting the metal to form theprojection lb before the profiling operation takes place, it isunnecessary to confine the edges or marginal portions of the stripduring the profiling operation and thus, the whole of the profiling maybe effected by the use of rollers as described adapted to avoid theapplication 'of any pressure on stretched parts or parts liable tostretching and consequent thinning.

As illustrated in Figure 7, a U section may be produced in a similarmanner by first forming two projecting ribs lb and then profiling thestrip in the manner before described Obviously, any other profiledsection may be produced in accordance with the invention. Furthermore,the projecting rib lb may be otherwise shaped, for example, to produce abulbous enlargement, such as shown at id in Figure 8. Furthermore, theinvention is applicable for the production oi. sections having beadingsor flanges le at the which there is m ing tendency.

edges, as shown in Figure 9, or at any other positions.

If required for the production of more complicated sections, two or moreupsetting operations, with or without preliminary local heating, maytake place simultaneously or in series.

It will be understood that the invention is not limited to theparticular embodiments hereinbefore described and that sections oi anydesired profile reinforced at the bend or bends or other positions maybe produced.

Although the inventio'n is of general application for the production ofprofiled sections by rolling from sheet metal, it is particularlyapplicable for use in connection with the method and apparatus accordingto my further copending applications, Serial Numbers 149,216 and149,218, both filed June 19, 1937. Furthermore, the rollers utilised forcarrying the invention into effect may be constructed according to mycopending application, Serial No. 149,219, filed June 19,

What I claim and desire to secure by Letters Patent is:

A method of preventing metal strips of substantially uniform thicknessfrom having undesirably weak zones when rolled from substantially fiatmaterial into structural members of .altered cross-sectional shape,comprising the steps of locally heating the strip in a longitudinal zonewhere the corner, enlargement or re-enforcement is to be formed, andimmediately subjecting the strip to rolling while exerting pressure onthe unheated portions of the strip towards the locally heated zonewhereby the material of said locally heated zone is upset.

EMIL PENKALA.

